Sewing machine feed mechanism



May 1, 1951 S. ERDELYl I SEWING MACHINE FEED MECHANISM 2 Sheets-Sheet 1 Filed April 20, 1948 11A L E m ME T m f m m ma "M /w; 4

Filed April 20, 1948 I y 1951 s. ERDELYI 2,551,108

SEWING MACHINE FEED MECHANISM 2 Sheets-Sheet 2 Fig.3

INVE NTOR SE GE ERDELYI 5,61%

AGENTS Patented May 1, 1951 S G MAGHIN'E ED MEQHANISM Serge Erdelyi, Vienna, Austria, assignor to O wxn r Lord nna, A i

Application April 20, 1948, Serial No. 22,076 In Austria January 1%)47 Claims- 1 Ihe invention relates to a sewing machine feed mechanism in which a feeding organ, advancing the -=stulf to be sewn, is provided which is substantially moved along a rectangular path under he action of two rocking shafts, journaled in the base of the machine body, and preferably actuated by the. needle bar shaft whereby said feeding. organ, preferably constituted by a toothed jaw, is arranged on an independently supported carrierfmovable in two planes perpendicular to each. other. With the known devices of this kind the stuff feeding organ carrier is made into a sliding-jaw, shiftably supported on a second sliding jaw, whereby the two jaws are actuated in two directions perpendicular to each other by means of cranlgs fastened to the rocking shafts. The result is a rather complicated and intricate design of the stuff feed mechanism, which appears unsuited for the high sewing speeds desired (high number of strokes of the feeding organ).

The invention eliminates this drawback, its main feature being that the feeding organ carrier is formed by a plate elastically reacting in one direction e. g. the perpendicular direction, saidfplate being tiltablysupported in the machine body base about an axle located substantially in parallel to the aforesaid direction.

The elastic behaviour of the feeding organ carrier plate in regard to the perpendicular direction is obtained either by inserting an elastic lamella into the plate in the neighbourhood of its point of supporter by suitably reducing the cross-section of the plate, preferably by milling. The feeding organ proper is tiltably supported on the carrying plate, and guided in a straight line through a slot in the so-called sieve plate.

Whereas by the first-mentioned feature the design of the feeding organ and/or the feeding organ carrying plate is considerably simplified, the last mentioned feature permits to obtain an irreproachably rectilinear motion of the feeding organ proper, so as to warrant a sensible improvement as to the/ operation of the feeding organ. According to an additional feature said improvement is enhanced by the operative connection with the lifting organ (pressure lever) controlled by one of the rocking shafts being rendered more positive by a particular spring load engaging the feeding organ carrying plate.

A further feature of the present invention consists in that of the two rocking shafts the one is made into a separate shaft, preferably held between bearing centers in a manner known, whilst the second is formed into a hollow shaft through the bore of which the gripper driving tive action of said mechanism.

The drawing illustrates the inventive idea by" way of embodiments,

Fig. 1 beinga part longitudinal section through the sewing machine, whereas F ig. 2 is a horizontal section taken on the line 2-2 of Fig. 1,

Fig. 3 across-section taken on the line 3-3 of Fig. 1,

Fig. 4 an analogous section taken on the line 4-4 of Fig. 1,

Fig. 5 is a lateral view of the feeding organ carrying plate, alone by itself,

Fig. 6 is a view thereon from above,

Fig. 7 is a part section through the supporting; area ofthe feeding organ carrying plate,

Fig. 8 is a part longitudinal section taken on the line 8--8 of Fig. 2 through the hollowrocking shaft housing the gripper shaft,

Figure 9 is a partial cross section taken through the portion of the carrying plate where the feed dog is mounted.

In the Figs. 1-3 the numerals I and 2 are used for designating the rocking shafts controlling the stuff feeding organ 3, said shafts deriving their motion, by way of connecting rods 0r pitmen 4, 5 and crank arms I, 2' from the eccentric-, cam-, or curve-drives 1, 8 fixed to the needle bar shaft 6. The feeding organ constituted in a manner known by a toothed jaw is, according to the invention, arranged on a carrier 9, preferably plateshaped, said carrier being qualified to execute movements in planes substantially perpendicular to each other. For this reason the carrier 9 of the embodiment illustrated is made to be elastic in the vertical direction, whilst for executing horizontal motions it is rotatable about a pin ll, fixed to the machine body base (refer to the Figs. 5 and 6). The elasticity or springiness of the plate 9 is brought about by a lamella l2 made of a highly elastic material, preferably spring steel, being inserted between the plate 9 and the support 9a. But the same effect might be achieved by imparting to the plate 9 itself a sufiiciently high degree of elasticity, or-as shown in Fig. '7-by suitably reducing the plate cross-section in the neighbourhood of the supporting area I2, preferably by arc-shaped millings l3 provided on one or on both sides. In any case, the degree of elasticity is so selected or determined that the plate will always snugly contact the lifting organ described below. Under certain circumstances for this purpose a spring load may be provided engaging the plate e. g. formed by a helical spring M, as visible in the Figs. 1, 5 and 6.

For compelling the feeding organ 3 to follow a rectangular path alternative movements (motions by turns) are imparted to said organ, or its carrier ill in two directions perpendicular to each other whereby either of the rocking shafts l and 2 controls one of these movements. Forinstance, as clearl visible in Fig. 4, the rocking shaft I controls the perpendicular motion of the carrier by means of a lever is fitted with a pressure roll l5, said lever acting against the lower side of the plate 9 provided at that point with an enlarge'ment 9' and displacing it perpendicularly at the beginning and the end of the feed.

. The horizontal motion of the plate IQ is taken care of by the preferably forked lever ll fastened to the other rocking shaft 2, said lever coacting with apin-shaped counter-part l8 at the lower side of the plate.

The feeding jaw 3 itself is, at [9, supported on the. free end of the feeding organ carrying plate 9 so that the jaw directly guided in the feeding organ slot 29 of the stitching plate 2| executes a perfectly rectilinear movement during the oscillating motion of the plate 9 (Figs. 5 and 6).

Whilst the rocking shaft 2 controlling the horizontal motion of the feeding organ carrying plate is formed in a manner known into an ordinary solid shaft, preferably held between the centers 23, 24, the invention provides for the other rocking shaft I, journaled'at 25, 26 in the machine body base being made into a hollow shaft in the bore of which'theshaft 28 driving the gripper'Z'I (gripper shaft) is lodged. As Fig. 8 shows clearly the bore of the hollow shaft i is narrowed or reduced at least at one point (at 2511) so as to con- Stitute a bearing for the gripper shaft 28 whose secondbearing is arranged, at 29, in the machine body base.

The gripper shaft 28 is actuatedthrough the 4 perpendicular intermediate shaft 29 and the toothed transmission gearing 30, 3lalso by the needle bar shaft 6, which derives its rotation e. g. by the belt drive 32 from the electric motor 33.

What I claim is:

1. In a sewing machine including a stitching plate, a feeding mechanism comprising a feeddog having a serrated upper surface projecting upward through a slot in the stitching plate, said dog being supported by a flat feed-plate mounted on the machine body about a fixed vertical axle for oscillation in a horizontal plane, said plate being flexible in a vertical direction allowing a vertical movement of the plate, both movements being controlled by separate rocking shafts in such a manner that an essentially rectangular path of the feed-dog is obtained.

2. Feeding mechanism for sewing machines as claimed in claim 1 and wherein the feed-plate has a reduced cross-section near the axle for oscillation, thereby to impart flexibility to said plate.

3. In a sewing machine including a stitching plate and a needle bar shaft, a feeding mechanism as claimed in claim 1 further comprising a loop taker shaft driven by the needle bar shaft, one of the two rocking shafts controlling the feed-plate being a separate shaft, suitably held between centers in a known manner, the other being a hollow shaft accommodating the loop taker shaft.

4. Feeding mechanism for sewing machines as claimed in claim 3, said hollow shaft having its bore narrowed at least at one point to provide a bearing for the loop taker shaft.

SERGE ERDELYI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 23,789 Shaw et al. Apr. 26, 1859 228,913 Morley June 15, 1880 572,039 Willcox Nov. 24, 1896 802,789 Woodward Oct. 24, 1905 1,079,406 Gould Nov. 25, 1913 

